Molecular dynamics simulations of high-energy radiation damage in W and W–Re alloys

Abstract

High-energy collision cascades with an energy of up to 300 keV for the primary knock-on atom (PKA) have been initially simulated in W and W–Re alloys containing 5 or 10 at.% Re atoms using the molecular dynamics method with recently fitted W–Re interatomic potentials. The effects of PKA energy and Re concentration on defect production, defect clustering and states of dislocation loops have been quantitatively analysed. The results show that the presence of Re atoms does not significantly affect either the number of surviving defects or their clustered fractions. In addition, the interstitial dislocation loops are dominated by the 1/2<111> loops. Mixed interstitial loops with 1/2<111> and <100> Burgers vectors and interstitial loops that have the same Burgers vectors but are located on different habit planes have also been observed. Further analysis indicates that the pinning effect induced by the Re atom segregation leads to the lower mobility of the interstitial clusters and interstitial 1/2<111> loops in W–Re alloys than in pure W, which is expected to influence the subsequent evolution of radiation-induced defects in W–Re alloy.